Effect of the potential melting of the Greenland Ice Sheet on the Meridional Overturning Circulation and global climate in the future

Abstract

Multiple recent observations indicate an accelerated mass loss of the Greenland Ice Sheet since the mid-1990s. This increased ice sheet mass loss might be an evidence of global warming and could be related to elevated atmospheric greenhouse gas concentrations. Here, we use the National Center for Atmospheric Research Community Climate System Model version 3 to assess the potential influence of a shrinking Greenland Ice Sheet on the Atlantic Meridional Overturning Circulation (MOC), the surface climate, and sea level in the next two centuries under the IPCC A1B scenario with prescribed rates of Greenland Ice Sheet melting. Results show that a low rate of Greenland melting will not significantly alter the MOC. However a moderate or high rate of Greenland melting does make the MOC weaken further. This further weakened MOC will not make the global climate in the next two centuries cooler than in the late 20th century, but will lessen the warming, especially in the northern high latitudes. Moreover, the sea level changes due to steric effect and ocean dynamics could potentially aggravate the sea level problem near the northeast North America coast and the islands in the western Pacific region.